diff --git a/internal/audiobooks/abs/handler.go b/internal/audiobooks/abs/handler.go
index f73613bd..bb10106a 100644
--- a/internal/audiobooks/abs/handler.go
+++ b/internal/audiobooks/abs/handler.go
@@ -320,6 +320,14 @@ func (h *Handler) mountRoutes(r chi.Router) {
 			r.Post(prefix+"/me/item/{itemId}/bookmark", h.handleUpsertBookmark("bookmark_created"))
 			r.Patch(prefix+"/me/item/{itemId}/bookmark", h.handleUpsertBookmark("bookmark_updated"))
 			r.Delete(prefix+"/me/item/{itemId}/bookmark/{time}", h.handleDeleteBookmark)
+			// Collections — owner-gated CRUD with cross-user public reads.
+			r.Get(prefix+"/collections", h.handleListCollections)
+			r.Post(prefix+"/collections", h.handleCreateCollection)
+			r.Get(prefix+"/collections/{id}", h.handleGetCollection)
+			r.Patch(prefix+"/collections/{id}", h.handleUpdateCollection)
+			r.Delete(prefix+"/collections/{id}", h.handleDeleteCollection)
+			r.Post(prefix+"/collections/{id}/book/{bookId}", h.handleAddCollectionBook)
+			r.Delete(prefix+"/collections/{id}/book/{bookId}", h.handleRemoveCollectionBook)
 		}
 	})
 
diff --git a/internal/audiobooks/abs_collection_store.go b/internal/audiobooks/abs_collection_store.go
new file mode 100644
index 00000000..7bfb520d
--- /dev/null
+++ b/internal/audiobooks/abs_collection_store.go
@@ -0,0 +1,175 @@
+package audiobooks
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"github.com/Silo-Server/silo-server/internal/audiobooks/abs"
+)
+
+// ABSCollectionStore implements abs.CollectionStore against the
+// abs_user_collections + abs_collection_items tables (migrations
+// 149 + 150). One row per collection in the parent table; one row
+// per (collection_id, library_item_id) in the items table.
+type ABSCollectionStore struct {
+	Pool *pgxpool.Pool
+}
+
+// Compile-time assertion.
+var _ abs.CollectionStore = (*ABSCollectionStore)(nil)
+
+func (s *ABSCollectionStore) ListUserCollections(ctx context.Context, userID, profileID string) ([]abs.Collection, error) {
+	uid, err := strconv.Atoi(userID)
+	if err != nil {
+		return nil, fmt.Errorf("abs_collection_store: invalid user id %q: %w", userID, err)
+	}
+	rows, err := s.Pool.Query(ctx, `
+		SELECT id, user_id, profile_id, name, description, is_public, created_at, updated_at
+		FROM abs_user_collections
+		WHERE user_id = $1
+		  AND COALESCE(profile_id, '00000000-0000-0000-0000-000000000000'::uuid)
+		      = COALESCE($2::uuid, '00000000-0000-0000-0000-000000000000'::uuid)
+		ORDER BY created_at DESC`,
+		uid, profileArg(profileID),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("abs_collection_store: list: %w", err)
+	}
+	defer rows.Close()
+	out := make([]abs.Collection, 0)
+	for rows.Next() {
+		var c abs.Collection
+		var uidScan int
+		var profileScan *string
+		if err := rows.Scan(&c.ID, &uidScan, &profileScan, &c.Name, &c.Description, &c.IsPublic, &c.CreatedAt, &c.UpdatedAt); err != nil {
+			return nil, fmt.Errorf("abs_collection_store: list scan: %w", err)
+		}
+		c.UserID = strconv.Itoa(uidScan)
+		if profileScan != nil {
+			c.ProfileID = *profileScan
+		}
+		out = append(out, c)
+	}
+	return out, rows.Err()
+}
+
+func (s *ABSCollectionStore) GetCollection(ctx context.Context, id string) (abs.Collection, error) {
+	var c abs.Collection
+	var uidScan int
+	var profileScan *string
+	row := s.Pool.QueryRow(ctx, `
+		SELECT id, user_id, profile_id, name, description, is_public, created_at, updated_at
+		FROM abs_user_collections WHERE id = $1`, id)
+	if err := row.Scan(&c.ID, &uidScan, &profileScan, &c.Name, &c.Description, &c.IsPublic, &c.CreatedAt, &c.UpdatedAt); err != nil {
+		if err.Error() == "no rows in result set" {
+			return abs.Collection{}, abs.ErrNotFound
+		}
+		return abs.Collection{}, fmt.Errorf("abs_collection_store: get: %w", err)
+	}
+	c.UserID = strconv.Itoa(uidScan)
+	if profileScan != nil {
+		c.ProfileID = *profileScan
+	}
+	return c, nil
+}
+
+func (s *ABSCollectionStore) CreateCollection(ctx context.Context, c abs.Collection) error {
+	uid, err := strconv.Atoi(c.UserID)
+	if err != nil {
+		return fmt.Errorf("abs_collection_store: invalid user id %q: %w", c.UserID, err)
+	}
+	if _, err := s.Pool.Exec(ctx, `
+		INSERT INTO abs_user_collections (id, user_id, profile_id, name, description, is_public)
+		VALUES ($1, $2, $3::uuid, $4, $5, $6)`,
+		c.ID, uid, profileArg(c.ProfileID), c.Name, c.Description, c.IsPublic,
+	); err != nil {
+		return fmt.Errorf("abs_collection_store: create: %w", err)
+	}
+	return nil
+}
+
+func (s *ABSCollectionStore) UpdateCollection(ctx context.Context, c abs.Collection) error {
+	if _, err := s.Pool.Exec(ctx, `
+		UPDATE abs_user_collections
+		   SET name = $2, description = $3, is_public = $4, updated_at = now()
+		 WHERE id = $1`,
+		c.ID, c.Name, c.Description, c.IsPublic,
+	); err != nil {
+		return fmt.Errorf("abs_collection_store: update: %w", err)
+	}
+	return nil
+}
+
+func (s *ABSCollectionStore) DeleteCollection(ctx context.Context, id string) error {
+	if _, err := s.Pool.Exec(ctx, `DELETE FROM abs_user_collections WHERE id = $1`, id); err != nil {
+		return fmt.Errorf("abs_collection_store: delete: %w", err)
+	}
+	return nil
+}
+
+func (s *ABSCollectionStore) ListCollectionItems(ctx context.Context, collectionID string) ([]abs.CollectionItem, error) {
+	rows, err := s.Pool.Query(ctx, `
+		SELECT collection_id, library_item_id, added_at
+		FROM abs_collection_items
+		WHERE collection_id = $1
+		ORDER BY added_at ASC`, collectionID)
+	if err != nil {
+		return nil, fmt.Errorf("abs_collection_store: list-items: %w", err)
+	}
+	defer rows.Close()
+	out := make([]abs.CollectionItem, 0)
+	for rows.Next() {
+		var it abs.CollectionItem
+		if err := rows.Scan(&it.CollectionID, &it.LibraryItemID, &it.AddedAt); err != nil {
+			return nil, fmt.Errorf("abs_collection_store: list-items scan: %w", err)
+		}
+		out = append(out, it)
+	}
+	return out, rows.Err()
+}
+
+func (s *ABSCollectionStore) AddCollectionItem(ctx context.Context, collectionID, libraryItemID string) error {
+	tx, err := s.Pool.Begin(ctx)
+	if err != nil {
+		return fmt.Errorf("abs_collection_store: begin tx: %w", err)
+	}
+	defer tx.Rollback(ctx)
+	if _, err := tx.Exec(ctx, `
+		INSERT INTO abs_collection_items (collection_id, library_item_id)
+		VALUES ($1, $2)
+		ON CONFLICT (collection_id, library_item_id) DO NOTHING`,
+		collectionID, libraryItemID,
+	); err != nil {
+		return fmt.Errorf("abs_collection_store: add-item: %w", err)
+	}
+	if _, err := tx.Exec(ctx, `UPDATE abs_user_collections SET updated_at = now() WHERE id = $1`, collectionID); err != nil {
+		return fmt.Errorf("abs_collection_store: bump-parent: %w", err)
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return fmt.Errorf("abs_collection_store: commit: %w", err)
+	}
+	return nil
+}
+
+func (s *ABSCollectionStore) RemoveCollectionItem(ctx context.Context, collectionID, libraryItemID string) error {
+	tx, err := s.Pool.Begin(ctx)
+	if err != nil {
+		return fmt.Errorf("abs_collection_store: begin tx: %w", err)
+	}
+	defer tx.Rollback(ctx)
+	if _, err := tx.Exec(ctx, `DELETE FROM abs_collection_items WHERE collection_id = $1 AND library_item_id = $2`,
+		collectionID, libraryItemID,
+	); err != nil {
+		return fmt.Errorf("abs_collection_store: remove-item: %w", err)
+	}
+	if _, err := tx.Exec(ctx, `UPDATE abs_user_collections SET updated_at = now() WHERE id = $1`, collectionID); err != nil {
+		return fmt.Errorf("abs_collection_store: bump-parent: %w", err)
+	}
+	if err := tx.Commit(ctx); err != nil {
+		return fmt.Errorf("abs_collection_store: commit: %w", err)
+	}
+	return nil
+}
diff --git a/internal/audiobooks/service.go b/internal/audiobooks/service.go
index b2a1bc2e..371a02f8 100644
--- a/internal/audiobooks/service.go
+++ b/internal/audiobooks/service.go
@@ -97,6 +97,11 @@ func (s *Service) BuildABSHandler(deps ABSHandlerDeps) *abs.Handler {
 		bookmarkStore = &ABSBookmarkStore{Pool: deps.Pool}
 	}
 
+	var collectionStore abs.CollectionStore
+	if deps.Pool != nil {
+		collectionStore = &ABSCollectionStore{Pool: deps.Pool}
+	}
+
 	var configProvider abs.ConfigProvider
 	if deps.Settings != nil {
 		configProvider = &ABSConfigProvider{Settings: deps.Settings}
@@ -133,6 +138,7 @@ func (s *Service) BuildABSHandler(deps ABSHandlerDeps) *abs.Handler {
 		ProgressStore:        progressStore,
 		PlaybackSessionStore: playbackSessionStore,
 		BookmarkStore:        bookmarkStore,
+		CollectionStore:      collectionStore,
 		SocketIO:             socketServer,
 		CoverResolver: func(ctx context.Context, path, variant string) string {
 			if deps.Detail == nil {